The present invention relates generally to devices that permit a suspension system to connect to an axle housing, and more particularly, to devices welded to the axle housing that permit active components of a suspension system to be connected to the axle housing. The present invention is further directed to a method of welding such devices to the axle housing.
A basic object of any suspension system in a vehicle is to suspend the vehicle body above the vehicle wheels. To achieve this end, suspension systems are typically connected between the axle, or its housing, and the vehicle frame. Suspension systems typically include active components, such as springs and the like, to keep the sprung mass (vehicle body) suspended above the unsprung mass (vehicle wheels). A suspension system preferably permits a relatively smooth, yet stable, ride during acceleration, deceleration and cornering of the vehicle, and during jounce and rebound of the axle when the vehicle is driven over bumpy surfaces and the like.
In vehicles, one or more devices are sometimes welded to the axle housing to provide means for connecting the vehicle suspension to the axle housing. An example of such an arrangement is disclosed in U.S. Pat. No. 4,227,716, issued to Nordstrom, the disclosure of which is hereby incorporated herein by reference. As disclosed therein, and as shown in FIGS. 1-5 of the accompanying drawings, an axle housing 20 having a differential gear housing 22 at a central portion thereof is connected between vehicle wheels 24 positioned on opposite sides of a vehicle. Axle connection devices 26, which shall later be described in further detail, are welded to the front and rear faces of axle housing 20 in close proximity to each vehicle wheel 24. These connection devices 26 provide means for connecting a vehicle suspension 30 to the axle housing 20.
The vehicle includes a frame 32 extending longitudinally down each side of the vehicle. The vehicle suspension 30 is connected between the vehicle frame 32 and the axle housing 20 to suspend the vehicle body (not shown) above the vehicle wheels 24. The vehicle suspension 30 shown and described in U.S. Pat. No. 4,227,716, and in FIGS. 1-2 of the accompanying drawings, is generally known in the art as a Hotchkiss-type suspension. As shown, the suspension includes a main multi-leaf leaf spring pack 34 and an auxiliary multi-leaf leaf spring pack 36. The leaf springs that form the main leaf spring pack 34 are bundled together by a series of ties 38. The proximal end of the main leaf spring pack 34 is pivotally connected to a hanger 40, which in turn is fixedly mounted to the vehicle frame 32. The distal end of the main leaf spring pack 34 is connected to another hanger 42, which is also fixedly mounted to the vehicle frame 32. The distal end, however, is connected to hanger 42 through a shackle 44 that permits the distal end to move during deflection of the main leaf spring pack. The central portion of the main leaf spring pack 34 is seated on axle seating 46.
The auxiliary leaf spring pack 36 is seated on, and separated from the main leaf spring pack 34 by, a spacer 48. The leaf springs that form the auxiliary leaf spring pack 36 are bundled together by ties 50. Under normal circumstances, the auxiliary leaf spring pack 36 is inactive. However, if the vehicle is heavily loaded, the opposite ends of the auxiliary leaf spring pack 36 will engage against brackets 52, which are fixedly mounted to frame 32. This, in turn, will cause auxiliary leaf spring pack 36 to deflect during heavy vehicle load conditions.
Several components, a few of which have already been identified, hold the main and auxiliary leaf spring packs together. Those components also connect the leaf spring packs to the axle housing 20. In this arrangement, the threaded ends of two U-bolts 54 are inserted through bores extending through a guide plate 56, which is positioned atop the auxiliary leaf spring pack 36. The U-bolt ends are also inserted through bores extending through the axle seating 46 and bores extending through each of the axle connection devices 26. Nuts 58 are then tightened to the threaded ends of U-bolts 54 to tighten the entire assembly.
FIGS. 3-5 illustrate the axle connection devices 26 shown and described in U.S. Pat. No. 4,227,716. As shown, these devices include a baseplate 60 having circular ends 62 and a relatively short and narrow waist 64 dividing the ends. As such, the shape of baseplate 60 is similar to the symbol used to identify the mathematical concept of infinity. This shape permits the welds that connect the baseplate to the axle housing to withstand the forces exerted upon it during torsion of the axle housing.
A horizontal plane 65 projects outwardly from baseplate 60. Horizontal plane 65 includes a relatively flat and horizontally projecting upper surface 66 and a relatively flat and horizontally projecting lower surface 67. Upper surface 66 is generally parallel with lower surface 67. Horizontal plane 65 also includes a waist 68 correspondingly positioned with waist 64 of baseplate 60 to divide plane 65 into two portions, each having a bore 70 extending straight through it. Bores 70 accommodate the threaded ends of U-bolts 54 when the leaf spring packs 34, 36 are connected to the axle housing 20. Each axle connection device 26 is welded to the axle housing 20 by way of a continuous weld 72 formed along the edge of baseplate 60 and extending about its entire perimeter.
Although these axle connection devices have proven suitable for permitting connection of a vehicle suspension to an axle housing, they have had some drawbacks. As will be appreciated by those skilled in the art, each vehicle make and model typically has its own set of pinion angles for each of its axles. The set of pinion angles used for one vehicle is typically not the same used for another. Furthermore, the pinion angle used for one axle of a vehicle is typically not the same used for another axle of that vehicle. All of this considered, it will be appreciated by those skilled in the art that axle housings typically are not positioned so that they extend straight up and down. Rather, they are rotated to an extent to accommodate the required pinion angle.
In light of the construction of the aforementioned axle connection devices, it was often necessary to use additional parts and components to attach the vehicle suspension to the axle housing. These additional parts and components were required in order to accommodate the pinion angle. Such additional parts and components might, for instance, be uniquely designed shims or washers. Use of these additional parts and components added weight and expense to the suspension system, and required additional worker time and expense to design these components and to position, assemble and service them while the suspension system is connected to the axle housing.
As will also be appreciated by those skilled in the art, axle housings are ordinarily constructed in two halves that are fused or welded together. Often, the two axle housing halves have at least a slight mismatch, and use of the above-described axle connection devices required use of additional parts and components to accommodate this mismatch. Again, this added considerable weight and expense to the suspension system design, and required additional worker time and expense to design these components and to position, assemble and service them while the suspension system is connected to the axle housing.
Another drawback of these welded axle connection devices is that they were welded to the axle housing by a continuous weld run that traversed about the entire perimeter of the device. Use of this much metal added significant weight to the vehicle and amounted to additional expense. In practice, it has been typically necessary to use a continuous triple pass weld about the entire perimeter of the device to hold it to the axle housing. This even further added to the weight of the vehicle and amounted to even further additional expense.
In light of the foregoing, it is desirable to reduce the weight of vehicles that include welded axle connection devices.
It is also desirable to reduce the expense associated with such vehicles.
It is further desirable to eliminate the necessity of including additional components in such vehicles.
It is yet further desirable to design a welded axle connection device that has built-in features to accommodate varying pinion angles.
It is still further desirable to design a welded axle connection device that has built-in features to accommodate axle housing mismatch.
It is also desirable to design a welded axle connection device and devise a method for welding the device to an axle housing so that substantially less metal is used during the welding process.
These and other objects of the preferred form of the invention will become apparent from the following description. It will be understood, however, that an apparatus or method could still appropriate the invention claimed herein without accomplishing each and every one of these objects, including those gleaned from the following description. The appended claims, not the objects, define the subject matter of this invention. Any and all objects are derived from the preferred form of the invention, not necessarily the invention in general.
The present invention is directed to an axle connection device that is designed to be welded to an axle housing to permit a vehicle suspension system to be connected to the axle housing. The axle connection device includes a generally flat baseplate having curvilinear ends separated by a relatively long and narrow waist. Each end includes a curvilinear side rim and two rounded corners from which the rim of the baseplate smoothly tapers towards the waist. The device also includes a generally horizontally projecting plane having a waist aligned with the waist of the baseplate to divide the plane into two distinct portions. The plane also has two supporting sidewalls. Both sidewalls extend from just inside the rounded corners of a respective end of the baseplate and taper towards associated corners of the horizontally projecting plane. Each portion of the plane includes a generally rounded boss extending from the plane. A slot extending from the intersection of the baseplate and the plane is incorporated in each boss to allow a connection bolt to pass through the device. The construction of the device permits it to accommodate varying pinion angles and axle housing mismatch.
The present invention is also directed to a method of welding an axle connection device to a face of an axle housing. The method includes forming two continuous welds along both longitudinal edges of the device. Each weld begins longitudinally inward of one of the rounded corners of the device, preferably one of the rounded corners positioned closest to the spindle end of the axle. The weld is formed such that it extends longitudinally outwardly towards that rounded corner to a weld end, which is positioned longitudinally inward of that corner. The weld is then turned back on itself and extends longitudinally inwardly along the tapering slope of the end of the device towards the waist portion thereof to form a double-pass weld at its end. The weld then extends through the waist portion, then longitudinally outwardly along the tapering slope of the opposite end of the device to a point just shy of the rounded corner at that end. At that point, the weld is again turned back on itself to form a double-pass weld at its end. The weld is then terminated. Another continuous weld is made in like fashion along the opposing longitudinal edge of the device. Under this method, substantially less weld is used and the weld lines do not traverse over, along and/or around the rounded corners of the device. As a result, the axle housing (as opposed to the weld runs) primarily absorbs any torsional loading.